title: Changes in gene expression in human meibomian gland dysfunction.
abstract: OBJECTIVE
  Meibomian gland dysfunction (MGD) may be the leading cause of dry eye syndrome throughout the world. However, the precise mechanism(s) underlying the pathogenesis of this disease is unclear. This study was conducted to identify meibomian gland genes that may promote the development and/or progression of human MGD.
  
  
  METHODS
  Lid tissues were obtained from male and female MGD patients and age-matched controls after eyelid surgeries (e.g., to correct entropion or ectropion). Meibomian glands were isolated and processed for RNA extraction and the analysis of gene expression.
  
  
  RESULTS
  The results show that MGD is associated with significant alterations in the expression of almost 400 genes in the human meibomian gland. The levels of 197 transcripts, including those encoding various small proline-rich proteins and S100 calcium-binding proteins, are significantly increased, whereas the expression of 194 genes, such as claudin 3 and cell adhesion molecule 1, is significantly decreased. These changes, which cannot be accounted for by sex differences, are accompanied by alterations in many gene ontologies (e.g., keratinization, cell cycle, and DNA repair). The findings also show that the human meibomian gland contains several highly expressed genes that are distinct from those in an adjacent tissue (i.e., conjunctival epithelium).
  
  
  CONCLUSIONS
  The results demonstrate that MGD is accompanied by multiple changes in gene expression in the meibomian gland. The nature of these alterations, including the upregulation of genes encoding small proline-rich proteins and S100 calcium-binding proteins, suggest that keratinization plays an important role in the pathogenesis of MGD.
authors.affiliation: Schepens Eye Research Institute, Boston, MA 02114, USA.
authors.forename: Shaohui
authors.initials: S
authors.lastname: Liu
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Richards
authors.forename: Kristine
authors.initials: K
authors.lastname: Lo
authors.forename: Mark
authors.initials: M
authors.lastname: Hatton
authors.forename: Aaron
authors.initials: A
authors.lastname: Fay
authors.forename: David A
authors.initials: DA
authors.lastname: Sullivan
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000075982:Cell Adhesion Molecule-1; D015815:Cell Adhesion Molecules / Q000235:genetics; D062465:Claudin-3; D055233:Cornified Envelope Proline-Rich Proteins / Q000235:genetics; D015352:Dry Eye Syndromes / Q000235:genetics*; D005141:Eyelid Diseases / Q000235:genetics*; D005260:Female; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000502:physiology*; D006801:Humans; D007136:Immunoglobulins / Q000235:genetics; D008297:Male; D008537:Meibomian Glands / Q000502:physiology*; D008565:Membrane Proteins / Q000235:genetics; D008875:Middle Aged; D020411:Oligonucleotide Array Sequence Analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D009418:S100 Proteins / Q000235:genetics
chemical_list: C403514:CADM1 protein, human; C568122:CLDN3 protein, human; D000075982:Cell Adhesion Molecule-1; D015815:Cell Adhesion Molecules; D062465:Claudin-3; D055233:Cornified Envelope Proline-Rich Proteins; D007136:Immunoglobulins; D008565:Membrane Proteins; D009418:S100 Proteins